centos7下apache2.4反向代理

apache安装目录在/data/apache24，这里就不介绍apache的安装了。

一、反向代理配置

在/data/apache24/conf/extra下创建htttpd-proxy.conf文件

#开启反代理的必须模块
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
LoadModule slotmem_shm_module modules/mod_slotmem_shm.so
LoadModule lbmethod_byrequests_module modules/mod_lbmethod_byrequests.so
LoadModule lbmethod_bytraffic_module modules/mod_lbmethod_bytraffic.so
LoadModule lbmethod_bybusyness_module modules/mod_lbmethod_bybusyness.so

#关闭正向代理
ProxyRequests Off
#设置集群组，mycluster名称可以随意取
<Proxy "balancer://mycluster">
    BalancerMember http://192.168.1.222:8080
    BalancerMember http://192.168.1.233:8080
</Proxy>
#使用集群组，mycluster名称需与上面配置相同
ProxyPass "/demo" "balancer://mycluster/"
ProxyPassReverse "/demo" "balancer://mycluster/"

修改/data/apache24/conf/httpd.conf中添加

Include conf/extra/htttpd-proxy.conf

这样重启apache后，当我们访问网站/demo时，会反向代理到222和233上的8080端口。

二、apache负载均衡管理界面

<Location "/balancer-manager">
    SetHandler balancer-manager
    order Deny,Allow
    Deny from all
    Allow from localhost
</Location>

访问网站/balancer-manager时，就可以看到apache自带的一个负载均衡管理界面。

三、虚拟主机上配置反向代理

<VirtualHost *:80>
    DocumentRoot "/data/wwwroot/test"
    ServerName www.test.com
    ErrorLog "logs/www.test.com-error_log"
    CustomLog "logs/www.test.com-access_log" common
    #当我们访问www.test.com时，都会代理到mycluster集群中。
    ProxyPass "/" "balancer://mycluster/"
    ProxyPassReverse "/" "balancer://mycluster/"
</VirtualHost>

四、负载比例分配

loadfactor取值范围为1-100

ProxyRequests Off
<Proxy "balancer://mycluster">
    BalancerMember http://192.168.1.222:8080 loadfactor=6
    BalancerMember http://192.168.1.233:8080 loadfactor=4
    BalancerMember http://192.168.1.244:8080 loadfactor=2
</Proxy>
ProxyPass "/" "balancer://mycluster/"
ProxyPassReverse "/" "balancer://mycluster/"

五、负载分配算法

lbmethod取值有：
lbmethod=byrequests 按照请求次数均衡(默认)
lbmethod=bytraffic 按照流量均衡
lbmethod=bybusyness 按照繁忙程度均衡(总是分配给活跃请求数最少的服务器)

ProxyRequests Off
<Proxy "balancer://mycluster">
    BalancerMember http://192.168.1.222:8080 loadfactor=6
    BalancerMember http://192.168.1.233:8080 loadfactor=4
    BalancerMember http://192.168.1.244:8080 loadfactor=2
</Proxy>
ProxyPass "/" "balancer://mycluster/"
ProxyPassReverse "/" "balancer://mycluster/"
ProxySet lbmethod=bytraffic

五、热备份

请求总是流向222，一旦222挂掉， apache会检测到错误并把请求分流给233。apache会每隔几分钟检测一下222的状况，如果222恢复，就继续使用222。

ProxyRequests Off
<Proxy balancer://mycluster>
    BalancerMember http://192.168.1.222:8080
    BalancerMember http://192.168.1.233:8080 status=+H
</Proxy>
ProxyPass "/" "balancer://mycluster/"
ProxyPassReverse "/" "balancer://mycluster/"